/*-------------------------------------------------------------------------*
* PL_CALL_PROLOG *
* *
* Call_Prolog runs the execution of one prolog goal. *
* The current choice point is updated to set ALTB to Call_Prolog_Fail and *
* CP is set to Call_Prolog_Success. At the end ALTB and CP are restored. *
* To ensure that a choice point always exists before invoking Call_Prolog,*
* Start_Prolog reserve the space for a feint choice point, i.e ALTB can be*
* safely modified. *
* *
* Call_Prolog returns TRUE if the predicate has succeed, FALSE otherwise. *
* The called predicate can be non-deterministic. *
*-------------------------------------------------------------------------*/
Bool
Pl_Call_Prolog(CodePtr codep)
{
WamWord *query_b = B;
WamCont save_CP = CP;
WamCont save_ALTB = ALTB(query_b);
Bool ok;
ALTB(query_b) = (CodePtr) Call_Prolog_Fail; /* modify choice point */
CP = Adjust_CP(Call_Prolog_Success);
#if defined(_WIN32) || defined(__CYGWIN__)
SEH_PUSH(Win32_SEH_Handler);
#endif
ok = Call_Next(codep);
#if defined(_WIN32) || defined(__CYGWIN__)
SEH_POP;
#endif
CP = save_CP; /* restore continuation */
ALTB(query_b) = save_ALTB; /* restore choice point */
return ok;
}
/*-------------------------------------------------------------------------*
* PL_CALL_PROLOG_NEXT_SOL *
* *
* Call_Prolog_Next_Sol bactracks over the next solution. *
*-------------------------------------------------------------------------*/
Bool
Pl_Call_Prolog_Next_Sol(WamWord *query_b)
{
WamCont save_CP = CP;
WamCont save_ALTB = ALTB(query_b);
Bool ok;
ALTB(query_b) = (CodePtr) Call_Prolog_Fail; /* modify choice point */
CP = Adjust_CP(Call_Prolog_Success); /* should be useless since */
/* alternative will restore CP */
ok = Call_Next(ALTB(B));
CP = save_CP; /* restore continuation */
ALTB(query_b) = save_ALTB; /* restore choice point */
return ok;
}
/*-------------------------------------------------------------------------*
* PL_CALL_PROLOG *
* *
* Call_Prolog runs the execution of one prolog goal. *
* The current choice point is updated to set ALTB to Call_Prolog_Fail and *
* CP is set to Call_Prolog_Success. At the end ALTB and CP are restored. *
* To ensure that a choice point always exists before invoking Call_Prolog,*
* Start_Prolog reserve the space for a feint choice point, i.e ALTB can be*
* safely modified. *
* *
* Call_Prolog returns TRUE if the predicate has succeed, FALSE otherwise. *
* The called predicate can be non-deterministic. *
*-------------------------------------------------------------------------*/
Bool
Pl_Call_Prolog(CodePtr codep)
{
WamWord *query_b = B;
WamCont save_CP = CP;
WamCont save_ALTB = ALTB(query_b);
Bool ok;
ALTB(query_b) = (CodePtr) Call_Prolog_Fail; /* modify choice point */
CP = Adjust_CP(Call_Prolog_Success);
ok = Call_Next(codep);
CP = save_CP; /* restore continuation */
ALTB(query_b) = save_ALTB; /* restore choice point */
return ok;
}